Ray Huang famously attributed the collapse of late imperial China in part to the nonsensical complexity of its tax quotas, which needed to be calculated to the tenth decimal place (almost literally to the exact grain of rice), to the point that tax clerks basically exhausted themselves just clacking the abacus all day. I always thought this was a crank view, but after spending the past couple years actually examining Ming-Qing tax data I’m coming around to it. All the figures on these pages assess miniscule, marginal tax situations for a sub-district of one county (total pop. ~160,000), many of which categories brought in enough revenue annually to pay for maybe a nice dinner for two, if you went light on the drinks.

Then at the very end (after over a dozen pages of this) you get the normal tax on normal people without weird exemptions that 95% of the money comes from, and which takes probably 1% of total accounting effort to handle. A time traveler who really wanted to save the Ming wouldn’t need to show them electricity or guns or anything, just convincing them to round to the second decimal would probably make a big difference.